MOTION
79
79. Dimensions and Units of Velocity. — The dimensions of velocity are [LT™1]. The C.G.S. unit of velocity is the
cm centimeter per second, —'. The British unit of velocity is
sec*
the foot per second, - *: •
sec*
80. Rectangular Components of Velocity. — Let v, Fig. 48,
Y
X
FIG. 48.
denote the velocity at P, then the magnitude of its component along the re-axis is
vx = v cos 0
da
= ~ cos 0 at
dt
Similarly and
dz
(ii)
Equations (II) state that the component of the velocity of a particle along any line equals the velocity of the projection of the particle upon that line, in other words, the ve-